Learning and memory Flashcards
what is an engram
a hypothetical permanent biochemical or physical change in the brain caused by a memory
how did Lashley’s experiments provide evidence for the theory of engrams
puts rats in mazes
showed that large areas of cerebral cortex had to be destroyed in order to prevent learning of complex tasks and this had little effect on simple tasks
where do we currently think engrams are located
places related to processing the memory
what is associative learning
As cells fire simultaneously they increase the synaptic associations. This
results in networks of cells which are synaptically linked
what is habituation
– decrease in response (& NT release ) with repeated stimulus
what is sensitisation
increase in response with repeated stimulation - mediated by an interneurone
what is long term potentiation
a long term increase in synaptic strength following high frequency stimulation of a chemical synapse
aka a strengthening of synpapses between cells
what is long term depression
a reduction in the eficacy of synapses following a long patterned stimulus
what is short term memory
a very brief memory, either from an external stimulus or retrieval of a long term memory
can be displaced by another stimulus
can be extended into working memory by repition in a phonic loop, or chunking which links familiar chunks together
what is working memory
the maintenence and integration of information in an active state to a breif time in order to acheive a short term task
may be the repeated reactivation of short term memory or recalled long term memory
after may be encoded into long term memory or elapse
what can long term memory be subdivided into
declarative (Conscious) and non declarative (unconscious)
what part of the brain is involved in declarative memory
medial temporal lobe
what part of the brain is involved in non declarative memory
lower areas of the brain- hypothalamus, amygdala, basal ganglia and cerebellum
what are some of the components of non declarative memory
procedural- habits and skills
habituation, sensitisation, conditioning, emotianal responses
what are the 4 parts of memory
encoding, storage, retrieval, consolidation
describe the process of memory formation
events are encoded in the hippocampus, and a reference is made to their memory location- hippocampal index
If this information is recalled prior to consolidation, the hippocampus performs the
retrieval from its index of the events
After consolidation of the memory retrieval can be initiated directly from the sensory
cortices
how can PTSD be treated
plasticity in the long term memory- pts are asked to relive events leading to the PTSD and then given a beta blocker which blocks re consolidation
what is consolidation a result of
physical/ morphological changes at the synapse
LTM is predominantly in the cortex
what structures are involved in consolidating non declarative memory involving movement and procedural memory
corpus striatum (caudate nucleus and putamen
what type of memory is the cerebelum involved in
fine motor learning including speech movements
describe patient HM
operation to remove part of the medial temporal lobes bilaterally to treat epilepsy
describe the effects on HM
profound retrograde and anterograde amnesia
inability to remember people he had just met, his age, the death of his mother
inability to consolidate declarative long term memories
no effect on perception, intelligence or personality
was able to learn non declarative memories
what is dissociated amnesia
amnesia occuring without any other deficits
what structures can cause anterograde amnesia
anterior or dorsomedial nuclei of the thalamus, Mammillary
bodies, temporal lobes
what is the role of the dorsomedial nucleus of the thalamus
receives input from temporal lobe structures like the amygdala which is then relayed to the frontal cortex- executive function
what is the role of the diencephalon in amnesia
there is a functional link between between the dorsomedial thalamus and the medial temporal lobe in memory consolidation
what lesion can cause a loss of non declarative memory
striatum of the basal nuclei
involved in huntingtons disease
